diff --git a/go/observer/main.go b/go/observer/main.go
new file mode 100644
index 0000000..e3b2a91
--- /dev/null
+++ b/go/observer/main.go
@@ -0,0 +1,79 @@
+package main
+
+import "fmt"
+
+/*
+实例：
+汤宝宝一时想不开，当了房产中介。
+一旦片区内有房东发布了新房源信息，他就会第一时间通知所有潜在租客。
+*/
+
+// 观察者抽象接口
+type Observer interface {
+	Update()
+}
+
+// 目标抽象接口
+type Subject interface {
+	Attach(observer Observer)
+	Detach(observer Observer)
+	Notify()
+}
+
+// 具体目标 - 房产中介
+type HousingAgency struct {
+	observers []Observer
+}
+
+func (h *HousingAgency) Attach(observer Observer) {
+	h.observers = append(h.observers, observer)
+}
+
+func (h *HousingAgency) Detach(observer Observer) {
+	for i, obs := range h.observers {
+		if obs == observer {
+			h.observers = append(h.observers[:i], h.observers[i+1:]...)
+			break
+		}
+	}
+}
+
+func (h *HousingAgency) Notify() {
+	fmt.Println("房产中介通知了所有租客。")
+	for _, observer := range h.observers {
+		observer.Update()
+	}
+}
+
+// 具体观察者 - 租客
+type Tenant struct {
+	name string
+}
+
+func (t *Tenant) Update() {
+	fmt.Printf("租客%s收到了房源更新通知。\n", t.name)
+}
+
+func main() {
+	fmt.Println("============= 观察者模式 =============")
+
+	agency := &HousingAgency{}
+
+	tenant1 := &Tenant{name: "小明"}
+	tenant2 := &Tenant{name: "小红"}
+
+	fmt.Println("小红和小明订阅了房产中介的房源信息。")
+	agency.Attach(tenant1)
+	agency.Attach(tenant2)
+	fmt.Println("房源上新了！")
+	agency.Notify()
+
+	fmt.Println("-----")
+	fmt.Println("小红不想再接收房源信息，退订了。")
+	agency.Detach(tenant2)
+	fmt.Println("又有新房源了！")
+	agency.Notify()
+
+	fmt.Println()
+	fmt.Println("=========== 观察者模式结束 ===========")
+}
diff --git a/python/observer/main.py b/python/observer/main.py
new file mode 100644
index 0000000..0875ac4
--- /dev/null
+++ b/python/observer/main.py
@@ -0,0 +1,78 @@
+"""
+实例：
+汤宝宝一时想不开，当了房产中介。
+一旦片区内有房东发布了新房源信息，他就会第一时间通知所有潜在租客。
+"""
+
+from abc import ABC, abstractmethod
+
+
+# 抽象观察者类
+class Observer(ABC):
+    @abstractmethod
+    def update(self):
+        pass
+
+
+# 抽象目标接口
+class Subject(ABC):
+    @abstractmethod
+    def attach(self, observer: Observer):
+        pass
+
+    @abstractmethod
+    def detach(self, observer: Observer):
+        pass
+
+    @abstractmethod
+    def notify(self):
+        pass
+
+
+# 具体目标类
+class HousingAgency(Subject):
+    def __init__(self):
+        self._observers = []
+
+    def attach(self, observer: Observer):
+        self._observers.append(observer)
+
+    def detach(self, observer: Observer):
+        self._observers.remove(observer)
+
+    def notify(self):
+        print("房产中介通知了所有租客。")
+        for observer in self._observers:
+            observer.update()
+
+
+# 具体观察者类
+class Tenant(Observer):
+    def __init__(self, name: str):
+        self.name = name
+
+    def update(self):
+        print(f"租客{self.name}收到房源更新通知！")
+
+
+if __name__ == "__main__":
+    print("============= 观察者模式 =============")
+
+    agency = HousingAgency()
+    tenant1 = Tenant("小明")
+    tenant2 = Tenant("小红")
+
+    print("小红和小明订阅了房产中介的房源信息。")
+    agency.attach(tenant1)
+    agency.attach(tenant2)
+
+    print("房源上新了！")
+    agency.notify()
+
+    print("-----")
+    print("小红不想再接收房源信息，退订了。")
+    agency.detach(tenant2)
+    print("又有新房源了！")
+    agency.notify()
+
+    print("\n=========== 观察者模式结束 ===========")
diff --git a/ts/src/observer/index.ts b/ts/src/observer/index.ts
new file mode 100644
index 0000000..3312184
--- /dev/null
+++ b/ts/src/observer/index.ts
@@ -0,0 +1,82 @@
+/*
+实例：
+汤宝宝一时想不开，当了房产中介。
+一旦片区内有房东发布了新房源信息，他就会第一时间通知所有潜在租客。
+*/
+
+// 观察者抽象接口
+interface Observer {
+  update(): void;
+}
+
+// 目标抽象接口
+interface Subject {
+  attach(observer: Observer): void;
+  detach(observer: Observer): void;
+  notify(): void;
+}
+
+// 具体目标类
+class HousingAgency implements Subject {
+  private observers: Observer[];
+
+  constructor() {
+    this.observers = [];
+  }
+
+  attach(observer: Observer): void {
+    const isExist = this.observers.includes(observer);
+    if (isExist) {
+      return console.log("Observer has been attached already.");
+    }
+    this.observers.push(observer);
+  }
+
+  detach(observer: Observer): void {
+    const observerIndex = this.observers.indexOf(observer);
+    if (observerIndex === -1) {
+      return console.log("Nonexistent observer.");
+    }
+    this.observers.splice(observerIndex, 1);
+  }
+
+  notify(): void {
+    console.log("房产中介通知了所有租客。");
+    for (const observer of this.observers) {
+      observer.update();
+    }
+  }
+}
+
+// 具体观察者类
+class TenantObs implements Observer {
+  private name: string;
+
+  constructor(name: string) {
+    this.name = name;
+  }
+
+  update(): void {
+    console.log(`租客${this.name}收到了房源更新通知。`);
+  }
+}
+
+(function () {
+  console.log("============= 观察者模式 =============");
+  const agency = new HousingAgency();
+  const tenant1 = new TenantObs("小明");
+  const tenant2 = new TenantObs("小红");
+  console.log("小红和小明订阅了房产中介的房源信息。");
+  agency.attach(tenant1);
+  agency.attach(tenant2);
+  console.log("房源上新了！");
+  agency.notify();
+
+  console.log("-----");
+  console.log("小红不想再接收房源信息，退订了。");
+  agency.detach(tenant2);
+  console.log("又有新房源了！");
+  agency.notify();
+
+  console.log("\n=========== 观察者模式结束 ===========");
+})();